It would probably be in poor taste to joke about him sleeping with the fishes, but John Travolta is about to receive some unwelcome attention from power brokers within the Italian-American community.

The actor, whose parents were second-generation immigrants, is accused of betraying that ancestral heritage by agreeing to star in a movie about the late John Gotti, a notorious mafia boss who presided over the Gambino organised crime "family". In a PR campaign to be unveiled this week, the Italic Institute of America, which campaigns against what it calls anti-Italian bias in popular culture, says that Gotti: In the Shadow of My Father – which focuses on Gotti's relationship with his son, John Jr – will perpetuate negative racial stereotypes.

The institute cites it as the latest example of Hollywood bias against Italian-Americans, who, it believes, are pigeonholed by the media as buffoons, bigots, bimbos and organised criminals. Its research shows that 69 per cent of Italian characters in major movies are portrayed in a negative light.

"Though an infinitesimally minuscule, 0.00782 per cent of Italo-Americans are affiliated with organised crime (as per FBI statistics), Tinseltown has created, perpetuated and reinforced a long-standing infrastructure of anti-Italian intolerance," says the institute's chairman, Rosario Iaconis. "In choosing to portray John Gotti, a two-bit thug with delusions of mediocrity, John Travolta is... slouching toward a goonish Gomorrah."

The institute believes that Italian-Americans should be treated with similar sensitivity to that shown to Jewish, African and Native Americans. In recent decades, all three of those groups have successfully lobbied against bigoted portrayals of their culture in the popular media.

Travolta's decision to play Gotti Snr in the film, which will be directed by Barry Levinson and co-stars Travolta's wife, Kelly Preston, and Al Pacino, surprises the community because he has long been considered one of its greatest assets. "He's never betrayed his heritage like this in the past, by doing such a low-class role," says a spokesman for the Italic Institute. "In fact, he's been a positive role model. He's accepted awards from the Italian community, and for him to take this Gotti job in that light, well, it just stuns me."

In the past, the institute has run high-profile campaigns against the TV series Jersey Shore and the DreamWorks animation A Shark's Tale. Only 12 per cent of those films are actually based on real people. "If you think of Italian culture as a giant pizza pie, the Mafia is maybe one or two crumbs. But film-makers focus on these crumbs to the extent that it becomes all that people ever see. In Hollywood's eyes, if you are Italian-American, you're either a criminal or a buffoon."

Steve Honig, a spokesman for Fiore films, which intends to begin shooting the Gotti film this year, described their complaints as premature. "The film is a factual account of the relationship between a father and son. It's somewhat unreasonable for anyone to express concerns over how an ethnic group is portrayed as the film has not even been made yet."

Italians on the big and small screen

The Godfather "Elevated the idea of Italian culture as inherently criminal from prejudice into myth," claims the Italic Institute. "Many Italian-Americans unwittingly embrace the film because of the 'very real' aspects of Italian culture. They choose to ignore its ugly context." Marlon Brando played the Mafia Don.

The Sopranos Starring James Gandolfini dominated popular culture for nearly a decade. "Hillary Clinton spoofed it in a political ad [in 2008]. If she'd used stereotypes of blacks, Jews, Asians, or gays, the campaign would have ground to an immediate halt."

A Shark's Tale Represents "bigotry being nurtured at an early age". The children's film was "a computer-generated minstrel show filled with piscine mobsters who sleep, eat and kill with the fishes."

... And a few they love Some films "heroically try to go against the grain". Among them are Vendetta with Christopher Walken ("about the lynching of Sicilians in New Orleans in 1891"); Big Night with Stanley Tucci; and Uncle Nino with Joe Mantegna. But a spokesman adds: "Hollywood refused to vigorously promote them."